Do you trust a negative STD test result?

I had symptoms of an STD, my Dr thought it was an STD. This was 6 weeks after my first and only experience having genital contact with some else. My Dr tested me right then and there and it came back that I was negative for all STDs. Although, I've read that tests can be wrong, especially if you test within only 3 months. It's been 9 months now and I've had no symptoms of it. But some say it can lay dormant for a while and show up years later.